1. Field of the Invention
The present invention relates to a wide-angle shooting apparatus for shooting a wide-angle image and an optical device constituting the shooting apparatus. More particularly, it relates to a wide-angle shooting apparatus and the like that are used for a camera built in a vehicle, a door phone or the like for checking a safe condition.
2. Description of Related Art
FIG. 1 is a diagram for illustrating a past wide-angle shooting apparatus. The past wide-angle shooting apparatus 51 has a reflecting conical mirror 52 and a camera unit 53. The camera unit 53 has a pinhole for focusing light to a focal point and a two-dimensional image sensor 55.
The apparatus 51 also has a camera-processing unit 56 and a conversion-processing unit 57, which are used for processing image data shot in the image sensor 55.
In the past wide-angle shooting apparatus 51, the image sensor 55 of the camera unit 53 receives light L reflected by the reflecting conical mirror 52 to shoot an image. Thus, the image sensor 55 shoots a semicircular image 58.
The camera-processing unit 56 receives and processes the image data from the image sensor 55 to transmit data of the semicircular image 58. The conversion-processing unit 57 performs coordinate conversion on the data of the semicircular image 58 on the basis of a center of circle for the semicircular image into data of rectangular image 59 such that its angle measure and a distance from the center of circle can be conformed to the rectangular image. This allows the rectangular image to be converted from the semicircular image.
Alternatively, it has been proposed in Japanese Patent Application Publication No. 2003-163819 that a wide-angle shooting apparatus is capable of shooting a wide-angle image by combining plural reflecting mirrors.